Light-sensitive color-photographic emulsions

ABSTRACT

WHEREIN R1 is a hydrogen atom or a methyl group; R2 is a hydrogen atom or an aliphatic hydrocarbon residue having one to 16 carbon atoms; R3 is an aliphatic hydrocarbon residue having one to 18 carbon atoms; n is zero or 1; and X is a hydrogen atom, a halogen atom, or a substituted or unsubstituted phenylazo group.   A light-sensitive silver halide color-photographic emulsion, characterized by containing a cyan coupler represented by the general formula

United States Patent 72] Inventors Masakuni Iwama;

lsaburo lnoue; Yutaka Takei; Toshihiko Yamamoto; Takayo Endo, Tokyo, allof Japan 21] Appl. No. 868,579

22] Filed Oct. 22, 1969 45] Patented Nov. 9, 1971 73] AssigneeKonishiroku Photo Industry Co., Ltd.

Tokyo, Japan 32] Priority Oct. 24, 1968 33] Japan 54] LIGHT-SENSITIVECOLOR-PHOTOGRAPHIC EMULSIONS 6 Claims, No Drawings 52] US. Cl 96/100,96/55, 260/202, 260/471 A 51] Int. Cl G03c l/40 50] Field of Search 96/l 00 56] References Cited UNITED STATES PATENTS 2,375,344 5/1945Bruylants et a1. 96/100 2,474,293 6/ l 949 Weissberger et a1 96/1001,562,528 7/1951 Corner 96/100 1,418,129 12/1968 Kimura et a1. 96/1003,459,552 8/1969 Yoshida et a1. 96/100 3,481,741 12/1969 Yoshida et a1.96/100 3,488,193 1/1970 Eynde et a1. 96/100 Primary Examiner.lohn T.Goolkasian Assistan! Examiner-George W. Moxon, ll Attorney-Waters,Roditi, Schwartz and Nissen ABSTRACT: A light-sensitive silver halidecolor-photographic emulsion, characterized by containing a cyan couplerrepresented by the general formula wherein R is a hydrogen atom or amethyl group; R is a hydrogen atom or an aliphatic hydrocarbon residuehaving one to 16 carbon atoms; R, is an aliphatic hydrocarbon residuehaving one to 18 carbon atoms; :1 is zero or 1; and X is a hydrogenatom, a halogen atom, or a substituted or unsubstituted phenylazo group.

This invention relates to light-sensitive color-photographic emulsionscontaining novel cyan couplers which are soluble in water-immisciblehigh-boiling solvents.

As couplers for use in light-sensitive color-photographic emulsions,there are known the so-called Agfa type couplers which are soluble inwater, and the so-called protected couplers which are soluble inwater-immiscible high-boiling solvents It is well known that dye imagesobtained by colordeveloping protected couplers contained in the emulsionlayers of light-sensitive color-photographic materials have, in general,excellent stability to light, heat, humidity and chemicals fordevelopment as compared with those of the Agfa type couplers.

Heretofore, various compounds have been synthesized for use as protectedcouplers. Almost all of these, however, have disadvantages in that theyare low in solubility for high-boiling solvents, they easily deposit inemulsions and coatings, the starting materials therefor are expensive,and the procedures for the synthesis thereof are complex which make themexpensive. For example, the coupler of the formula i tCsHu which isdisclosed in U.S. Pat. No. 2,474,293, has excellent solubility forhigh-boiling solvents. This coupler, however, uses a very expensivestarting material and is only difficulty purified. A coupler synthesizedfrom a higher fatty acid or higher aliphatic amine, e.g. the couplerofthe formula wherein R is a hydrogen atom or a methyl group; R is ahydrogen atom or an aliphatic hydrocarbon residue having one to 16carbon atoms; R;, is an aliphatic hydrocarbon residue having one to 18carbon atoms; n is zero or I; and X is lhydrogen atom, a halogen atom ora substituted or unsubstituted phenylazo group.

These couplers which are used in the present invention, can overcome thedisadvantages of the conventional couplers by displaying the followingcharacteristics:

(CHDa a I. They are easily soluble in such high-boiling solvents asdibutyl phthalate, tricresyl phosphate and N ,N-dibutyl laurylamide, sothat the amounts of high-boiling solvents to be added to the couplerscan be decreased and stable dispersions of high concentration can beobtained.

2. They are low in melting point and do not deposit in emulsions or incoatings. r

3. They can be synthesized by a short process, they can be easilyseparated and purified, they are high in yields and are inexpensive inproduction costs.

4. They give dye images which have desirable spectral absorptioncharacteristics and are fast to light, heat, humidity and chemicals.

Thus, the couplers employed in the quite useful as protected couplers.

Accordingly, light-sensitive color-photographic emulsions incorporatedwith the couplers of the present invention can be maintained stablywithout any deterioration in photographic characteristics due todeposition of the couplers.

present invention are Typical couplers employed in the present inventionare set forth below, but these are mere examples and the couplers usablein the present invention are not limited only to these.

(1) N-Dodecyloxycarbonyl-mo bi1OX \Ci1li)Oll \l me thy l-1-hydroxy-2-nap hthamido COHNCHgCOOCHgCOOCuIIss (.\1.l. 74-74.5C.)

(2)N[1-(ethoxyearbonyl)pentadecyloxycarbonylmethyl]-1-hydroxy-2-naphthamidoCOIINCII C O ()(IUIC O O CglI (M. P. 575!lC.)

( u cv (4) N-[1-(dodecyloxycarbonyl)-cthoxycarbonylmothyl]l-hydroxy-2-naphthamide on oouNcmo0031110000211 my. 55 we.) J n,

(6) N-[l-(dodecyloxycarbonyl-motlloxycurl)onyl)- ethyl]-1-hvdroxy-2-napht llzunido (7) N -[2-(dodecyloxycarbonyl-methoxycarbonyl)-ethyl]-l-hydroxy-2-naphthamide l \-c OHNCHzCHzC o CHzC 000121125 (M.P. e0.)

(8) N -dodecy10xycarbonyl-methoxycarbonylmethyl-1-hydroxy-4-ehloro-2-naphthamide (9)N-dodecyloxycarbonyl-methoxycarbonylmethyll-hydroxyl- (Z-acetylphenylaz0) -2-naphtharnide @3-0 OHNCH C O O CH COOCuHzs (M.P. 133137C l COCH:

(1 O) N-[ 1- (dodecyloxycarbonyl) -et;hoxycarbony1- methyl1-l-hydroxy-4-Z-acetylp henylaz 0) -2 naphthamide ,-ooHN c1120 0 0 mo 0 0 (3121125(M.P. los aon o.)

| COCH:

(1 1) N-[ l-(butoxycarbonyl)-heptyloxycarbonylmethyl]-1-hydroxy-4-(Z-acetylphenylazo)-2- naphthamideCOCH:

(13) N-[2-(dodecyloxycarbonyl-mcthoxycarbonyl)-ethyll-l-hydr0xy-4-(2-ethoxycarbonylphenylazo)-2- naphthamideCOHNCHZCHZCOOCI'DCOO CizHes (M.P 137138 C.)

l COOC5H (14) N-[(l-methylheptyl)-0xycarbonyl methoxycarbonylmcthyl)]-1-hydr0xy-4-( 2-ethoxycarbonylphenylazo)-2-naphthamide COOC IL;

wherein X, R and as defined above. and then this intermediate is formedinto a potassium salt and is reacted in dimcthylformamide with an alkylester of an u-halo-fatty acid or said intermediate is reacted indimethylformamide with an alkyl ester of halo-fatty acid in the presenceof acidic potassium carbonate.

Synthesis of the couplers is exemplified below in detail. Synthesis ofthe coupler l) a. l-Hydroxy-Z-naphthoylglycine 84 g. of potassiumhydroxide are dissolved in a mixed solution of200 ml. ofwater and 400ml. ofalcohol and further I 12 g. of glycine are dissolved therein. Tothe resulting solution are added 164 g. of phenyl-l-hydroxy-Z-naphthoateand 400 ml. of alcohol and the solution is boiled under reflux for 3hours. The solution is poured into 3 kg. of ice water and then filteredin an ordinary manner with activated charcoal. To the filtrate are added160 ml. of concentrated hydrochloric acid and the precipitate separatedthereby is filtered with suction. washed with water and pressed. The wetprecipitate is then taken up in 2 liters of alcohol and boiled underreflux to completely dissolve. The resulting solution is filtered in anordinary manner with activated charcoal. The filtrate together with 3liters of warmed water is allowed to stand and the resulting crystalsare filtered with suction, washed with 30 percent alcohol and dried togive g. of pale orange needle crystals melting at 207-209 C.

In the analogous manner, the following are obtained:

granulated sugarlike crystals of pale pinkl-Hydroxy-Z-naphthoyl-/3-alanine m.p. l49l50 C.; needle crystals of palepink b. Dodecyl-a-chloroacetate 94.5 g. of a-chloroacetic acid and 186.3g. of dodecyl alcohol are dissolved in L5 liters of dehydrated benzene.The solution added with 5 g. of p-toluenesulfonic acid is boiled underreflux for 2 to 3 hours and the water produced during the reaction iseliminated by azeotropic distillation with benzene. The reactionsolution is then shaken with aqueous sodium carbonate solution and thebenzene layer is dehydrated and distilled under reduced pressure toremove the benzene. Distillation of the residue gives 155 g. ofdodecyl-a-chloroacetate boiling at 187188 C./l4 mm.Hg. This product maybe used in the subsequent reaction stage even after benzene is distilledoff without effecting further distillation.

In an analogous manner, the following are obtained:

l-Methyl-heptyl-a-chloroacetate b.p. l20-l23 C./l3

mm.Hg.

Dodecyl-a-bromopropionate b.p. (decomp.); used without distillationButyl-a-bromo caproate used without distillation c)N-Dodecyloxycarbonyl-methoxycarbonylmethyl l hydroxy-2-naphthamide 123g. Of I-hydroxy-2-naphthoylglycine are dissolved in 600 ml. of methanoland mixed with a solution of 56 g. of potassium hydroxide in 600 ml. ofmethanol. Methanol is distilled off under reduced pressure. The residueis added with 1 liter of dimethylformamide and l3] g. ofdodecyl-achloroacetate and the mixture is heated with stirring for 2hours at a bath temperature of 95100 C. After standing to cool, thereaction mixture is poured into 10 liters of water and the separatedprecipitate is filtered with suction, washed with water and dried.Recrystallization from 1.5 liters of methanol gives 200 g. of theproduct and further recrystallization from 5 liters of n-hexane gives170 g. offlake crystals of pale pink.

In an analogous manner, the afore-said couplers (2)(7) are obtained.Synthesis ofthe coupler (8) 188 g. Of the coupler (l),N-dodecyloxycarbonyl-methoxycarbonylmethyl-l-hydroxy-Z-naphthamide, aredissolved in 500 ml. of chloroform. The resulting solution is cooled tobelow C. and mixed'with a mixed solution of 66 g. of sulfuryl chlorideand 200 ml. of chloroform. The solution is then allowed to stand at roomtemperature for 1 hour and solvent is removed by the distillation underreduced pressure. The residue is mixed with 1 liter of n-hexane andallowed to stand. The separated precipitate is filtered with suction,washed with n-hexane and dried to give 13 g. ofN-dodecyloxycarbonylmethoxycarbonylmethyl-l-hydroxy-4-chloro-2-naphthamide.Recrystallization from 1.3 liters of n-hexane gives 90 g. of powderlycrystals of pale brown, melting at 69-70 C. Synthesis of the coupler (9)H3 g. Of o-aminoacetophenone are dissolved in diluted hydrochloric acidand diazotized with an aqueous sodium nitrite solution. The resultingsolution is added to a solution of 471 g. of the coupler lN-dodecyloxycarbonyl-methoxycarbonylmethyl-l-hydroxy-Z-naphthamide in amixed solution of 4 liters of pyridine and 10 liters of acetonitrile ata temperature below 10 C. with stirring. Stirring is continued for 30minutes at room temperature and 400 ml. of concentrated hydrochloricacid is added to the reaction solution and the separated precipitate isfiltered with suction, washed with water and dried to give 550 g. ofN-dodecyloxy-carbonylmethoxycarbonylm ethyl- I -hydroxy-4-(2-acetylphenylazo-2- naphthamide. Recrystallization from ethyl acetategives 3 l 0 g. of featherlike red crystals.

in the above process, use of the couplers (4), (5) and (6) in place ofthe starting coupler (1) provides the aforesaid couplers (10),(l l and12), respectively.

The couplers (l3) and (I4) can be obtained from diazotized ethylo-aminobenzoate and the couplers (3) and (7), respectively.

Among the couplers employed in the present invention. those in which Xis a halogen atom can be synthesized by treating a coupler, in which Xis a hydrogen atom, with a halogenating agent such as sulfuryl chloride,thereby substituting the hydrogen atom with a halogen atom. Further,those in which X is a substituted or unsubstituted phenylazo group aresynthesized by coupling a coupler, in which X is a hydrogen atom, with asubstituted or unsubstituted aromatic diazonium compound.

Couplers of the aforesaid formula, in which R, and R are hydrogen atomsand R is a straight chain alkyl group, show excellent solubility forhigh-boiling solvents. However, they can be markedly enhanced insolubility by changing R to a methyl group; R to an alkyl group; R to abranched alkyl group; or n to l. R, can be changed by selecting, as thestarting material, glycine, a-alanine or B-alanine; R by selecting achloroacetic acid, a-bromopropionic acid, a-bromo-n-butyric acid,a-bromo-i-butyric acid, a-bromocaprylic acid or crbromolauric acid; R,,by selecting lauryl alcohol, 2-ethylhexyl alcohol, 2-octyl alcohol or7-ethyl-2-methyl-undecyl alcohol- 4; ,and n by selecting glycine orB-alanine. All these starting materials are easily obtainable,commercially available products. in the preparation of intermediatealso, alkyl esters of the a-halo-fatty acids are obtained by reacting ana-halofatty acid with an equimolar amount of an aliphatic alcohol andcan be synthesized with such high purity and yield. Further, thereaction of this intermediate with l-hydroxy-Z naphthoyl-amino acid canalso be carried out easily as mentioned previously, and the desiredproduct can be obtained with high purity and yield by simple isolationand purification operations.

Thus, the couplers employed in the present invention have suchadvantages that they can be synthesized through three and four steps,without necessitating any complex steps, from inexpensive and easilyobtainable starting materials and can be greatly reduced in productioncosts as compared with conventional couplers.

Using the couplers synthesized in the above manner, lightsensitivecolor-photographic materials are prepared in the following manner:

For example, a cyan coupler employed in the present invention isdissolved in a high-boiling solvent having a boiling point of more thanC. such as tricresyl phosphate or dibutyl phthalate, either singly or,if necessary, in admixture with a low-boiling solvent such as butylacetate or butyl propionate. This solution is mixed with an aqueousgelatine solution containing a surface active agent and is thenemulsified by means of a high speed rotary mixer or a colloid mill.Then, the thus formed coupler dispersion is directly added to a silverhalide photographic emulsion, which is coated onto a film base, a barytapaper or the like support, following by drying to remove a majorproportion of the low-boiling solvent. Alternatively, theabove-mentioned coupler dispersion is set and then extruded to noodleform, which is freed from the lowboiling solvent by water-washing or thelike means. Then the noodle is added with warming to a silver halidephotographic emulsion, which is then coated onto the aforesaid support,followed by drying.

The above-mentioned manner of incorporation of the coupler are merelyillustrative and are not limitative. The'amount of the coupler to beadded to the silver halide photographic emulsion is preferably in therange of lO-lOO g. per mole of silver halide, but is not always limitedthereto. As the silver halide employed in the photographic emulsion.there may be used such silver salts as silver chloride, silver iodide orsilver iodobromide. This emulsion may contain chemical sensitizers, e.g.sulfur sensitizers, natural sensitizers present in gelatine, reductivesensitizers and noble metal salts. The emulsion may further containordinary photographic additives such as, for example, antifoggants,stabilizers, antistain agents, antiirradiation agents, coating aids, andother high molecular additives. Furthermore, it may contain knowncarbocyanine dyes, merocyanine dyes, etc. as optical sensitizers.

The thus obtained light-sensitive color-photographic material is exposedto radioactive rays, X-rays, visible rays, infrared rays, etc., isdeveloped with a color-developing solution containing ap-phenylene-diamine type developer and is then bleached and fixed toobtain a cyan dye image favorable in transparency and high in resistanceto light, heat and humidity. The dye image is excellent in spectralabsorption characteristics and has a maximum absorption in the vicinityof 680-690 m,u. Alternatively, when a light-sensitive colorphotographicmaterial incorporated with an arylazo type coupler, which itself has areddish orange or red color as in the case of the coupler (l)exemplified previously, is exposed and is then treated according to theordinary color development process, there are simultaneously obtained acyan color negative image and a reddish orange to red color positiveimage. This positive color image serves, in printing the negative imageonto a positive material, as a mask for correcting the undesirableabsorptions in blue light and green light regions which arecharacteristic of the cyan color negative image. Preferable as couplersof this type are substituted phenylazo compounds having in the positionortho to the azo linkage, an alkoxycarbonyl group or a fatty acyl group.

Typical developing agents employed in developing the lightsensitivecolor-photographic materials of the present invention include sulfates,sulfites and hydroehlorides of N,N- diethyl-p-phenylenediamine,N-ethyl-N- B-methane-sulfonamidoethyl-3-methyl-4-aminoaniline,N-ethyl-N-hydroxyp-phenylenediamineN-ethyl-N-hydroxy-2-methyl-p-phenylenediamine andN,N-diethyl2-methyl-p-phenylenediamine.

The present invention is illustrated in further detail below withreference to examples, but it is needless to say that the examples aremerely illustrative and the invention is not limited thereto.

EXAMPLE 1 20 g. of the previously exemplified coupler (l) were added toa mixed liquid comprising 20 ml. of dibutyl phthalate and 60 ml. ofbutyl acetate, and the mixture was completely dissolved at 80 C. Thissolution was mixed with 10 ml. of a 10 percent aqueous solution ofAlkanol B (alkyl naphthalene sulfonate produced by Du Pont) and 200 ml.ofa 5 percent aqueous gelatine solution, and the mixture was subjectedto a colloid mill to form a coupler dispersion. This coupler dispersionwas added to 1 kg. of a high speed gelatinous silver iodobromideemulsion, which was then coated onto a film base and was dried toprepare a light-sensitive color-photographic material having a stablecoating layer.

The thus prepared light-sensitive material was exposed according to anordinary procedure and was then developed at 20 C. for minutes with adeveloping solution of the following composition:

N,N-Diethyl-p-phenylenediamine hydrochloride 2.5 g. Anhydrous sodiumsulfite 2.0 g. Sodium carbonate (monohydrate) 82.0 g. Potassium bromide2.0 3. Water to make I000 ml.

Potassium ferricyanide 100 g. Potassium bromide 50 g. Water to make 1000ml.

The bleached material was further washed with water for 5 minutes andwas then fixed for 5 minutes with a fixing bath having the followingcomposition:

Sodium thiosulfale (pentahydrale) Water to make 250 g. 1000 ml.

Thereafter, the fixed material was washed with water for -25 minutes andwas then dried to obtain a brilliant cyan dye image having a maximumabsorption at 685 mu.

EXAMPLE 2 10 g. of the exemplified coupler (8) were added to a mixedliquid comprising 10 ml. of tricresyl phosphate and 30 ml. of butylacetate, and the mixture was completely dissolved at 60 C. This solutionwas mixed with 5 ml. ofa 10 percent aqueous solution of the followingcomposition: 1

Melhol 3.0 g. Anhydrous sodium sulfite 60.0 g. Hydroquinone 6.0 g.Anhydrous sodium carbonate 50.0 g. Potassium bromide l.0 g.

Water to make Subsequently, the developed material was subjected toordinary stopping and film-hardening treatments and to waterwashing.After subjecting it to second exposure by means ofa white light,- thematerial was developed at 20 C. for 12 minutes with a developingsolution of the following composition: 1

N.N-Diethyl-p-phenylenediaminc hydrochloride 5.0 Anhydrous sodiumsulfite 2.0 g. Sodium carbonate (monohydrate) 82. 1. Potassium bromidel.0 g. Water to make I000 ml.

Thereafter, the material was subjected to ordinary stopping, fixing.water-washing and bleaching treatments, was washed with running waterfor 20 minutes and was then dried to obtain a brilliant cyan colorpositive image having a maximum absorption at 685 mu.

EXAMPLE 3 10.0 g. of the exemplified coupler (4) were mixed with 20 ml.of dibutyl phthalate, and the mixture was completely dissolved at 50 C.This solution was mixed with 5 ml. ofa l0 percent aqueous solution ofAlkanol B and 200 ml. ofa 5 percent aqueous gelatine solution, and themixture was passed several times through a colloid mill to form adispersion. The disper sion was added to 500 g. of a gelatinous silverchlorobromide emulsion, which was then coated onto a baryta paper andwas dried to prepare a light-sensitive color-photographic material.

The thus prepared light-sensitive material was exposed and thendeveloped at 20 C. for 10 minutes with a developing solution ofthefollowing composition:

N-Ethyl-Nhydroxyethyl-pphenylenediaminc sulfate 25 g. Anhydrous sodiumsulfite 2.0 g. Hydroxyaminc hydrochloride 1.0g Sodium carbonate(monohydratc) 810g. Potassium bromide 2.0 g.

Water to make I000 ml.

Subsequently, the material was dipped in a stopping bath comprising 10ml. of glacial acetic acid, 3.0 g. of caustic soda and 1000 ml. ofwater, and was then immediately dipped for 4 minutes in an acidic.film-hardening fixing bath. Subsequently, the material was washed withwater for 10 minutes and was bleached at 20 C. for 8 minutes in a bathof the following composition:

EDTA ZNa (disodium salt of ethylencdiamine tetraacclic acid) 40.0 g.Ferric chloride 30.0 g. Sodium carbonate (monohydrate) 20.0 Potassiumbromide 30.0 g. Sodium thiosulfate (pentahydrate) 200.0 Water to makeI000 ml.

After washing with water for 20 minutes, the bleached material wasdipped in a stabilizing bath for 2 minutes and then dried to obtain acyan color image having a maximum absorption at 685 mp. which wasfavorable in resistance to light and heat and was excellent instability.

EXAMPLE 4 2.0 g. of the exemplified coupler (10) were added to a mixedliquid comprising 2 ml. of dibutyl phthalate and 6 ml. of butyl acetate,and the mixture was dissolved at 80 C. This solution was mixed with 1ml. ofa 10 percent aqueous solution of Alkanol B and 20 ml. of a percentaqueous gelatine solution, and the mixture was subjected to a colloidmill to form a coupler dispersion. The coupler dispersion was added to100 g. of a high speed gelatinous silver iodobromide emulsion, which wasthen coated onto a film base and dried to prepare a high-sensitivecolor-photographic material.

The thus prepared light-sensitive material was exposed according to anordinary procedure and was then treated with the same developingsolution as in example 1 to obtain a red positive image having a maximumabsorption at 500 mp. and a cyan color image having a maximum absorptionat 685 mu.

EXAMPLE 5 2.0 g. of the exemplified coupler (7) were dissolved in 5 ml.of butyl acetate. This solution was mixed with 1.5 ml. ofa percentaqueous solution of Alkanol B and 20 ml. of a 5 percent aqueous gelatinesolution, and the mixture was subjected to a colloid mill to form acoupler dispersion. The coupler dispersion was added to 100 g. of a redcolor-sensitive, high speed gelatinous silver iodobromide emulsion,which was then coated onto a film base and dried to prepare alight-sensitive color-photographic material. The thus preparedlight-sensitive material was exposed according to an ordinary procedureand was then developed with the same developing solution as in example 1to obtain a brilliant cyan color image having a maximum absorption at685 mu.

EXAMPLE 6 5.0 g. of the exemplified coupler (2) were added to a mixedliquid comprising 5.0 ml. of dibutyl phthalate and ml. of butyl acetate,and the mixture was dissolved at 60 C. This solution was mixed with 2.5ml. of a 10 percent aqueous solution of Alkanol B and 50 ml. of a 5percent aqueous gelatine solution, and the mixture was subjected to acolloid mill to form a coupler dispersion. The coupler dispersion wasadded to 500 g. of a red sensitized silver chloride emulsion, which wasthen coated onto a film base and dried.

On the other hand, 5.0 g. ofa-[3-(2,4-di-tertamyl-phenoxyacetamide)-benzoyll-2-methoxy-acetanilidewere dissolved and mixed with a gelatine solution in the same manner asabove to form a dispersion. The dispersion was added to 500 g. of asilver bromide emulsion, which was then coated onto the above-mentionedcoating to prepare a light-sensitive color-photographic material.

The thus prepared light-sensitive material was exposed to X-raysaccording to an ordinary procedure, was developed at C. for 10 minuteswith the same developing solution as in example I, and was subjected toordinary stopping and filmhardening treatments andto water-washing.After subjecting to second exposure by means of a yellow light (usingAgfa color Separation Filter L exposure time 30 seconds), the materialwas again developed at 20 C. for 10 minutes with the above-mentioneddeveloping solution, was subjected to ordinary stopping, fixing,bleaching and water-washing treatments, and was then dried to obtain ayellow color image with a blue background.

EXAMPLE 7 5.0 g. of the exemplified coupler (5) were added to a mixedliquid comprising 5.0 ml. of dibutyl phthalate and l5 ml. of butylacetate, and the mixture was completely dissolved by heating to 60 C.This solution was mixed with 2.5 ml. ofa 10 percent aqueous solution ofAlkanol B and 50 ml. of a 5 percent aqueous gelatine solution, and themixture was subjected to a colloid mill to form a coupler dispersion.The coupler dispersion was added to 500 g. of a high speed silveriodobromide emulsion, which was then coated onto a film base and driedto prepare a light-sensitive color-photographic material.

On the other hand, a gelatine layer having a thickness of about 5 u wasformed on a cellulose triacetate film base. Onto said gelatine layer wasspotted a thymidine solution, which had been labeled with tritium sothat the amount thereof corresponded to 10 ac. per cm Thereafter,spotting was repeated by doubling diluting of the said solution to forma standard radioactive source with a stepwedge 0N2 with respect toradioactivity.

The surface of this gelatine film was brought in close contact with thefilm surface of the above-mentioned light-sensitive color-photographicmaterial. After allowing it to stand for 15 hours, the light-sensitivematerial was subjected to the same development as in example I to obtaina brilliant cyan dye image showing the presence of radioactive substanceat the portion corresponding to the radioactive source.

What we claim is:

l. A light-sensitive silver halide color-photographic emulsion,comprising a cyan coupler represented by the general formula wherein R,is a hydrogen atom or a methyl group; R is a hydrogen atom or analiphatic hydrocarbon residue having one to 16 carbon atoms; R is analiphatic hydrocarbon residue having one to l8 carbon atoms; n is zeroor 1; and X is a hydrogen atom, a halogen atom, or a substituted orunsubstituted phenylazo group.

2. A light-sensitive silver halide color-photographic emulsion asclaimed in claim 1, in which said cyan coupler is N-[ l-(Dodecyloxycarbonyl-methoxycarbonyl) -ethyl]-l-hydroxy2 -naphthamide ofthe formula COHNCIIC ()OCII C O ()C13II35 3. A light-sensitive silverhalide color-photographic emulsion as claimed in claim 1, in which saidcyan coupler is N- [2(Dodecyloxycarbonyl-methoxycarbonyl) -ethyl] 1-hydroxy- 2-naphthamide of the formula l 3-o oIINomomc o o cmo o oGully,

4. A light-sensitive silver halide color-photographic emulsion asclaimed in claim 1, in which said cyan coupler is N-Dodecyloxycarbonyl-methoxycarbonylmethyll -hydroxy-4-chloro-2naphthamide ofthe formula 11 2. 5. A light-sensitive silverhalide color-photographic emul- 6. A light-sensitive silver halidecolor-photographic emulsion as claimed claim 1, in which said cyancoupler is N-[ lsion as claimed in claim 1, in which said cyan coupleris N-[2- (Dodecyloxycarbonyl-methoxycarbonyl) -ethyl]- l -l1ydroxy-4Dodecyloxycarbonyl-methoxycarbonyl) -ethyl l -hydroxy-4-(2-acetylphenylazo-2-naphthamide of the formula2-ethoxycarbonylphenylazo)-2-naphthamide of the formula 5 R I (I311 v V-c OHNCHzCHzCOOCHzCOOCnHu -0 OHN(|3H2COOCH2COOC12H24 i CH3 l0 l N=N vN=N C 0 O CZHS (I30 CH1

2. A light-sensitive silver halide color-photographic emulsion asclaimed in claim 1, in which said cyan coupler isN-(1-(Dodecyloxycarbonyl-methoxycarbonyl)-ethyl)-1-hydroxy-2-naphthamide of the formula
 3. A light-sensitivesilver halide color-photographic emulsion as claimed in claim 1, inwhich said cyan coupler is N-(2(Dodecyloxycarbonyl-methoxycarbonyl)-ethyl)1-hydroxy-2-naphthamide of the formula
 5. A light-sensitivesilver halide color-photographic emulsion as claimed in claim 1, inwhich said cyan coupler is N-(1-(Dodecyloxycarbonyl-methoxycarbonyl)-ethyl)-1-hydroxy-4-(2-acetylphenylazo)-2-naphthamide of the formula 6.A light-sensitive silver halide color-photographic emulsion as claimedin claim 1, in which said cyan coupler isN-(2-(Dodecyloxycarbonyl-methoxycarbonyl)-ethyl)-1-hydroxy-4-(2-ethoxycarbonylphenylazo)-2-naphthamide of theformula